<!-- /*
 * @Author: RDSunday 
 * @Date: 2020-03-23 16:12:29 
 * @Last Modified by:   RDSunday 
 * @Last Modified time: 2020-03-23 16:12:29 
 */ -->
<!-- 计算器 -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            /* border: none; */
            /* font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif; */
            margin: 0;
            /*  内容区域靠边*/
            padding: 0;
            /*  button padding 清空*/

        }
        .center {
            background-color: #fff;
            /* border-radius: 50%; */
            height: 600px;
            margin: auto;
            width: 600px;
            /* 要注释 */
            border: 1px solid #666;


        }
        h2 {
            color: #495678;
            font-size: 30px;
            display: block;
            text-align: center;      
            padding-top: 20px;      


        }
        form {
            background-color: #495678;
            box-shadow: 4px 4px #3d4a65;
            margin: 40px auto;
            padding: 40px 0 30px 40px;
            width: 280px;
            /* 注释 */
            border: 1px solid #666;
        }
        .btn {
            outline: none;
            cursor: pointer;
            font-size: 20px;
            height: 45px;
            margin: 5px 0 5px 10px;
            width: 45px;

        }
        .btn:first-child {
            margin: 5px 0 5px 10px;
        }
        .btn, #display, form {
            border-radius: 25px;
        }
        #display {
            outline: none;
            background-color: #98d1dc;
            /* 插入内部颜色 */
            box-shadow: inset 6px 6px 0 #3facc0;
            color: #dededc;
            font-size: 20px;
            height: 47px;
            text-align: right;
            width: 165px;
            padding-right: 10px;
            margin-left: 10px;
        }
        .number {
            background-color: #72778b;
            box-shadow: 0 5px #5f6680;
            color: #dededc;
        }
        .number:active {
            box-shadow: 0 2px #5f6680;
            -webkit-transform: translateY(2px);
  	-ms-transform: translateY(2px);
  	-moz-tranform: translateY(2px);
            transform: translateY(2px);
        }
        .operator {
            background-color: #dededc;
            box-shadow: 0 5px #bebebe;
            color: #72778b;

        }
        .operator :active {
            box-shadow: 0 2px #bebebe;
            -webkit-transform: translateY(2px);
  	-ms-transform: translateY(2px);
  	-moz-tranform: translateY(2px);
  	transform: translateY(2px);
        }
        .other {
            background-color: #e3844c;
            box-shadow: 0 5px #e76a3d;
            color: #dededc;
        }
        .other:active {
	box-shadow: 0 2px #e76a3d;
  	-webkit-transform: translateY(2px);
  	-ms-transform: translateY(2px);
  	-moz-tranform: translateY(2px);
  	transform: translateY(2px);
}
    </style>

</head>
<body>
    <div class="center">
        <h2>HTML CSS, JavaScript 计算器</h2>
        <a href="" target="_blank" ><i class="fa fa-gitee"></i></a>
        <form name="calculator">
            <input type="button" id="clear" class="btn other" value="C">
            <input type="text" id="display">
            <br>
            <input type="button" class="btn number" value="7" onclick="get(this.value);">
            <input type="button" class="btn number" value="8" onclick="get(this.value);">
            <input type="button" class="btn number" value="9" onclick="get(this.value)">
            <input type="button" class="btn number" value="+"onclick="get(this.value)">
            <br>
            <input type="button" class="btn number" value="4" onclick="get(this.value)">
            <input type="button" class="btn number" value="5" onclick="get(this.value)">
            <input type="button" class="btn number" value="6" onclick="get(this.value)">
            <input type="button" class="btn number" value="*" onclick="get(this.value)">
            <br>

            <input type="button" class="btn number" value="1" onclick="get(this.value)">
            <input type="button" class="btn number" value="2" onclick="get(this.value)">
            <input type="button" class="btn number" value="3" onclick="get(this.value)">
            <input type="button" class="btn number" value="-" onclick="get(this.value)">
            <br>
            <input type="button" class="btn number" value="0" onclick="get(this.value)">
            <input type="button" class="btn number" value="." onclick="get(this.value)">
            <input type="button" class="btn number" value="/" onclick="get(this.value)">
            <input type="button" class="btn number" value="=" onclick="calculates()">
            
        </form>
        
    </div>
    <script>
        /* limpa o display */ 
document.getElementById("clear").addEventListener("click", function() {
	document.getElementById("display").value = "";
});
/* recebe os valores */
function get(value) {
	document.getElementById("display").value += value; 
} 

/* calcula */
function calculates() {
	var result = 0;
	result = document.getElementById("display").value;
	document.getElementById("display").value = "";
	document.getElementById("display").value = eval(result);
};
    </script>
</body>
</html>